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24-501: The name comes from IJ and geul , a Dutch word meaning "the portion of a channel that often has to be dredged." When the IJgeul opened in 1982, the maximum draft was at 16.5 meters. In 2006, the Minister of Transport decided to deepen and extend the IJgeul. Public works have dredged the channel to 17.8 meters. In addition, the IJgeul was extended in length from 23 to 43 kilometers. Traffic

48-654: A bay , in the Dutch province of North Holland . It is known for being Amsterdam 's waterfront. The name IJ is derived from the West Frisian word ie , alternatively spelled ije , meaning 'water' and cognate with the English word ea . The name consists of the digraph ij which is capitalized as IJ . Today, the IJ is divided into two parts: The IJ is connected to the North Sea to

72-492: A new port , IJmuiden ("IJ's mouth") was built at its west end. The east end of the IJ polders near Amsterdam was given over to industry, and a large new seaport area was constructed. The Buiten-IJ hosted the mixed dinghy sailing events for the 1928 Summer Olympics in neighboring Amsterdam. It also hosted two events for the 1920 Summer Olympics in Antwerp . The nautical event SAIL Amsterdam takes place on and around

96-421: A new approach to the design of dikes and other water-retaining structures, based on an acceptable probability of overflowing. Risk is defined as the product of probability and consequences. The potential damage in lives, property, and rebuilding costs is compared with the potential cost of water defences. From these calculations follows an acceptable flood risk from the sea at one in 4,000–10,000 years, while it

120-407: A piece of land elevated above its surroundings, with the augmentative suffix -er and epenthetical -d- . The word has been adopted in thirty-six languages. The Netherlands is frequently associated with polders, as its engineers became noted for developing techniques to drain wetlands and make them usable for agriculture and other development. This is illustrated by the saying "God created

144-404: Is 90 vessels with a maximum draft per year. The Eurogeul , a similar but larger channel dug some years before for the port of Rotterdam . 52°27′36″N 4°30′00″E  /  52.46000°N 4.50000°E  / 52.46000; 4.50000 IJ (Amsterdam) The IJ ( Dutch: [ɛi] ; sometimes shown on old maps as Y or Ye ) is a body of water , formerly

168-597: Is one in 100–2,500 years for a river flood. The particular established policy guides the Dutch government to improve flood defences as new data on threat levels become available. Major Dutch polders and the years they were laid dry include Beemster (1609–1612), Schermer (1633–1635), and Haarlemmermeerpolder (1852). Polders created as part of the Zuiderzee Works include Wieringermeerpolder (1930), Noordoostpolder (1942) and Flevopolder (1956–1968) Several cities on

192-515: Is strictly regulated; vessels must follow the leading lights over the last 23 km, which are formed by the Hoge vuurtoren van IJmuiden and the Lage vuurtoren van IJmuiden . 18 km from the coast, a space was created so that in case of problems, it is possible for vessels to turn back. The Prostar Sailing Directions from 2006 provides detailed approach and restriction information. The average attendance

216-761: The Paraíba Valley region (in the state of São Paulo ) have polders on land claimed from the floodplains around the Paraíba do Sul river. Bangladesh has 139 polders, of which 49 are sea-facing, while the rest are along the numerous distributaries of the Ganges-Brahmaputra-Meghna River delta. These were constructed in the 1960s to protect the coast from tidal flooding and reduce salinity incursion. They reduce long-term flooding and waterlogging following storm surges from tropical cyclones . They are also cultivated for agriculture. The Jiangnan region, at

240-625: The Vecht (Utrecht) and the other with the North Sea. Connection with the North Sea has subsequently disappeared, while the IJ in the Middle Ages has expanded. This is due to the emergence of the Zuiderzee , itself a bay of the North Sea resulting from a number of storms. At the end of the Middle Ages , the IJ was a long and narrow brackish bay that connected to the Zuiderzee and stretched from Amsterdam in

264-477: The Yangtze River Delta , has a long history of constructing polders. Most of these projects were performed between the 10th and 13th centuries. The Chinese government also assisted local communities in constructing dikes for swampland water drainage. The Lijia (里甲) self-monitoring system of 110 households under a lizhang (里长) headman was used for the purposes of service administration and tax collection in

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288-531: The 11th century. The oldest extant polder is the Achtermeer polder, from 1533. As a result of flooding disasters, water boards called waterschap (when situated more inland) or hoogheemraadschap (near the sea, mainly used in the Holland region) were set up to maintain the integrity of the water defences around polders, maintain the waterways inside a polder, and control the various water levels inside and outside

312-407: The IJ. Polder A polder ( Dutch pronunciation: [ˈpɔldər] ) is a low-lying tract of land that forms an artificial hydrological entity, enclosed by embankments known as dikes . The three types of polder are: The ground level in drained marshes subsides over time. All polders will eventually be below the surrounding water level some or all of the time. Water enters

336-428: The air. Polders are at risk of flooding at all times, and care must be taken to protect the surrounding dikes. Dikes are typically built with locally available materials, and each material has its own risks: sand is prone to collapse owing to saturation by water; dry peat is lighter than water and potentially unable to retain water in very dry seasons. Some animals dig tunnels in the barrier, allowing water to infiltrate

360-542: The east to Velsen in the west. At its west end, only the natural dune ridge across the Dutch North Sea coast prevented the IJ, which grew ever larger through the centuries, from directly connecting to the North Sea and so making the North Holland peninsula nearly an island. By the seventeenth century, however, access to the IJ became difficult due to sand bars across its mouth, and ships becoming bigger, and it

384-570: The largest part of the IJ followed suit between 1865 and 1876, with only a small lake remaining at Amsterdam that was closed off from the Zuiderzee by the Oranje locks . At the same time, the North Sea Canal was constructed in the former IJ basin to provide Amsterdam with access to the sea again and revive its ailing port . It cut through the isthmus to connect to the North Sea near the town of Velsen;

408-477: The low-lying polder through infiltration and water pressure of groundwater , or rainfall, or transport of water by rivers and canals. This usually means that the polder has an excess of water, which is pumped out or drained by opening sluices at low tide . Care must be taken not to set the internal water level too low. Polder land made up of peat (former marshland) will sink in relation to its previous level, because of peat decomposing when exposed to oxygen from

432-545: The polder, with a liangzhang (粮长, grain chief) responsible for maintaining the water system and a tangzhang (塘长, dike chief) for polder maintenance. In Germany, land reclaimed by diking is called a koog . The German Deichgraf system was similar to the Dutch and is widely known from Theodor Storm 's novella The Rider on the White Horse . In southern Germany, the term polder is used for retention basins recreated by opening dikes during river floodplain restoration ,

456-479: The polder. Water boards hold separate elections, levy taxes, and function independently from other government bodies. Their function is basically unchanged even today. As such, they are the oldest democratic institutions in the country. The necessary cooperation among all ranks to maintain polder integrity gave its name to the Dutch version of third-way politics —the Polder Model . The 1953 flood disaster prompted

480-845: The polders into an inaccessible swamp, which allowed the Allied armies to stop the German army . The Netherlands has a large area of polders: as much as 20% of the land area has at some point in the past been reclaimed from the sea, thus contributing to the development of the country. IJsselmeer is the most famous polder project of the Netherlands. Some other countries which have polders are Bangladesh , Belgium , Canada and China . Some examples of Dutch polder projects are Beemster , Schermer , Flevopolder and Noordoostpolder . The Dutch word polder derives successively from Middle Dutch polre , from Old Dutch polra , and ultimately from pol- ,

504-558: The structure; the muskrat is known for this activity and hunted in certain European countries because of it. Polders are most commonly, though not exclusively, found in river deltas, former fenlands , and coastal areas. Flooding of polders has also been used as a military tactic in the past. One example is the flooding of the polders along the Yser River during World War I . Opening the sluices at high tide and closing them at low tide turned

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528-555: The west and the IJmeer to the east by a set of locks . There are several theories about the origins of the IJ. Perhaps it began as a stream, following a breakthrough in the dunes of Castricum . More likely, the IJ is a remnant of a northern arm of the Rhine delta . Finally, the IJ could also come from the lake Almere or Flevo . During the Roman period the IJ connected on one side with lake Flevo and

552-538: The world, but the Dutch created the Netherlands". The Dutch have a long history of reclamation of marshes and fenland, resulting in some 3,000 polders nationwide. By 1961, about half of the country's land, 18,000 square kilometres (6,800 sq mi), was reclaimed from the sea. About half the total surface area of polders in northwest Europe is in the Netherlands. The first embankments in Europe were constructed in Roman times. The first polders were constructed in

576-542: Was nearly impossible for seafaring vessels to reach the city of Amsterdam. At the same time, the bay gnawed away at the surrounding farmlands , almost connecting with the Haarlemmermeer (Lake Haarlem) and seriously threatening the cities of Haarlem and Amsterdam. Plans were put forth to reclaim both the Haarlemmermeer and the IJ and turn them into polders . The Haarlemmermeer was first, falling dry in 1852, and

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